High-Temperature Transport Properties of Yb4−xSmxSb3

Polycrystalline L4Sb3 (L = La, Ce, Sm, and Yb) and Yb4−x Sm x Sb3, which crystallizes in the anti-Th3P4 structure type (I-43d no. 220), were synthesized via high-temperature reaction. Structural and chemical characterization were performed by x-ray diffraction and electronic microscopy with energy-dispersive x-ray analysis. Pucks were densified by spark plasma sintering. Transport property measurements showed that these compounds are n-type with low Seebeck coefficients, except for Yb4Sb3, which shows semimetallic behavior with hole conduction above 523 K. By partially substituting Yb by a trivalent rare earth we successfully improved the thermoelectric figure of merit of Yb4Sb3 up to 0.7 at 1273 K

Influence of Pr on the magnetic structure of Er

Time-of-flight neutron diffraction has been used to determine the temperature dependence of the magnetic structure of three binary hexagonal Er-Pr alloys, Er90Pr10, Er80Pr20, and Er60Pr40. In overall agreement with magneto-thermal measurements performed on these compounds, the addition of Pr initially increases the Curie temperature and decreases the Neel temperature, observed at 20 K and 86 K, respectively, for pure Er. The neutron diffraction data for Er90Pr10, however, also clearly show that a ferromagnetic phase, with moments parallel to the c-axis, coexists with modulated structure components, with increasing temperature up to 35 K, above which a pure sine modulated structure sets in up to the Neel temperature at approximately 65 K. A similar behavior is observed for Er80Pr20, where the sine modulated phase is observed to disappear at 48 K. In sharp contrast, only one magnetic phase, identified as ferromagnetic with moments parallel to the c-axis, is observed for Er60Pr40 from low temperatures up to the Curie point at 35 K. The propagation vectors of the sine modulated phases are found to be temperature dependent

The nature of the first order isostructural transition in GdRhSn

We present structural, magnetic, thermal, magnetocaloric, and electrical transport properties of polycrystalline GdRhSn. Magnetization data show that it orders antiferromagnetically at T-N = 16.2 K. The compound has the ZrNiAl type hexagonal crystal structure at room temperature and undergoes a first order iso-structural transition in the paramagnetic state at 245 K. The unit cell volume change at the transition is small (-0.07%) but discontinuous, in agreement with the first-order nature of the transition observed by magnetic, transport, and heat capacity measurements. The anisotropic changes of the lattice parameters are Delta alpha/alpha = 0.28% and Delta c/c = 0.64% on cooling. A substantial change in the 4f and conduction electron hybridization, giving rise to an increased integrated DOS, occurs when the high temperature phase transforms to the low temperature phase. A moderate magnetocaloric effect at T-N (Delta S-M = 6.5 J/kg K and Delta T-ad = 4.5 K for Delta H = 50 kOe) has been measured using both magnetization and heat capacity data. (C) 2014 Elsevier B.V. All rights reserved

Magnetic, magnetocaloric and magnetoresistance properties of Nd(7)Pd(3)

Magnetic, magnetocaloric and magnetoresistance properties of the intermetallic compound Nd(7)Pd(3) have been investigated. It exhibits a first-order magnetic phase transition at its ferromagnetic ordering temperature (T(C) = 34 K). Just above the T(C), the magnetization isotherms exhibit a metamagnetic transition from the paramagnetic to a ferromagnetic state. In the immediate vicinity of T(C), a field change of only 10 kOe leads to the giant magnetocaloric effect of 13 J mol(-1) K(-1). For a field change of 50 kOe a large magnetoresistance of similar to 21% is observed near T(C). First-principles electronic structure calculations indicate that the first-order phase transition in Nd(7)Pd(3) may originate from the peculiar nature of the density of states near the Fermi level